Streptococcus mutans is a Gram-positive cocci, Facultative anaerobic bacterium commonly found in the human oral cavity and is a significant contributor to tooth decay. J Kilian Clarke first described the microbe in 1924.
The first colonizers of the tooth surface are mainly Neisseria spp. and streptococci, including S. mutans. The pioneer species changes the local environmental conditions through growth and metabolism thus allowing more fastidious organisms to further colonize after them,...

The toothbrush, consisting of a head of tightly clustered bristles mounted on a handle, is a tool used to clean the teeth and gums. The long handle allows for cleaning of hard-to-reach areas of the mouth. Usually toothpaste is used with the toothbrush to increase the effectiveness of the toothbrush. Toothbrushes are made of various sizes, bristle textures, etc. Most dentists suggest using soft bristled toothbrushes due to harder ones damaging enamel.
Pre-dating toothbrushes people used a...

A pivoted catch designed to fall into a notch on a ratchet wheel so as to allow movement in only one direction (e.g. on a windlass or in a clock mechanism), or alternatively to move the wheel in one direction.